Electric weft detector system for looms



1947. v. F. SEPAVICH ETAL 2,429,530

ELECTRIC WEFT DETECTOR SYSTEM FOR LOOMS Filed July 23, 1945 W fiymvz oles BY W Patented Oct. 21, 1947 ELEoTiuo wErT nETEoTon SYSTEM FOR LOOMS Victor F. Sepavlch and John C. Manoog, Worcester, Masa, assignors to Crompton 8; Knowles ,Loom Works, Worcester, Mass., a corporation of Massachusetts Application July 23, 1945, Serial No. 606,601

10 Claims. (Cl. 139273) This invention relates to a weft detecting system for looms and it is the generalobject of the invention to provide a highly sensitive but simple weft detecting system which is operated by a very brief contact between the weft detector and the depleted bobbin.

In the weaving of very fine wefts there is likelihood of abrasion or cutting of the thread when the bobbin is almost depleted if any considerable pressure is exerted by the detecting mechanism as it engages the thread, particularly if there be only a single wrap of thread between the detector and the bobbin. Electric weft detectors as heretofore made have required a considerable displacement of the detector to provide time for the operation of the detector controlled solenoid forming part of the detecting system. This time has been secured by setting the detector fingers rearwardly a considerable distance behind the front center position of the bobbin, thereby causing the bobbin to strike the detector a blow sufficiently strong to cut a single strand of weft between the detector fingers and the bobbin. If the detector fingers are set forwardly so that they have a small displacement when engaged by the substantially depleted bobbin the cutting will be reduced, but the contact at the bobbin will not allow time for the full energization of the electromagnetic device which initiates a change in loom operation. a

It is an important object of our present invention to provide electric means for storing electricity which flows whenindication is given by the detector and thereafter .deliver the stored electricity to energize an electromagnetic device sufilciently long to insure initiation of a change in loom operation. This result we conveniently accomplish by the use of a normally discharged electric condenser connected in parallel with the electromagnetic device and so related to the decontact can occur on either the positive or nega tive alternation of the current and still be effective to charge the condenser. The condenser may either be non-polarized. in which case it can be charged by either the positive or the negative alternation, or the condenser unit may consist of two polarized condensers connected in reverse order.to the detecting circuit so that one or the other of them will be charged on any alternation.

Electric weft detectors as heretofore constructed have generally been objectionable because of arcing when the detector fingers engage the bare metallic ferrule on the bobbin. This arcing has the effect of pitting or roughening the surfaces of the detector fingers which engage the yarn, thereby causing abrasion of those parts of the weft which are engaged by the detector fingers while sufilcient weft for continued weaving still remains on the bobbin. By the use of the aforesaid condenser the arcing and therefore the pitting of the detector fingers is eliminated.

In our copending application, Serial No. 606,- 600, filed on even date herewith, which is a continuation in part of our pending application, Se-

rial No. 586,754, filed April 5, 1945, we have shown tector circuit as to be charged whenever the detector fingers engage a depleted bobbin. The condenser can be charged in a very brief interval of time, after which it discharges less rapidly to prolong the flow of current through the electromagnetic device. 7

To adapt our invention to the usual sources of electric power and at the same time reduce the fire hazard we use a transformer having a secondary which supplies low voltage; The current from the secondary alternates in the same way as does the current in the power lines, and the aforesaid condenser is connected in series with the secondary by the detector when the latter contacts the conducting part of the bobbin. This a retaining condenser in parallel with the relay but energized by current which flows through an electronic tube.. The broader aspects of theretaining condenser and the function which it performs with respect to the relay are set forth and claimed in the aforesaid application, andthe present application relates more particularly to the type of circuit which does not require an electronic tube but wherein the condenser is charged by the small current which flows through the detector.

With these and other objects in view which will appear as the description proceeds, our invention resides in the combination and arrangement of parts hereinafter described and set forth.

In the accompanying drawings, wherein three forms of our invention are set forth,

Fig. l is a diagrammatic view of the detecting system showing the preferred form of our invention,

Fig. 2 is a view similar to part of Fig. 1 but shows a modification consisting of a series resistance in the discharge circuit which includes the condenser and the relay, and

Fig. 3 shows a second modification of part of the circuit shown in Fig. 1, wherein polarized condensers are used.

Referring particularly to Fig. 1, the bobbin B is provided with an electric conductor F, which may be a metallic ferrule normally covered by the weft of the bobbin but uncovered when the bobbin is depleted, or in the condition shown in Fig. 1. The detector D has right and left detector fingers or electrodes I and i I positioned for engagement with the ferrule F when the latter is bare and mounted for sliding forward movement in the detector D. The solenoid S is of a type which has been used in previous electric detecting systems and has a core 12 connected as at I3 to a lifter finger I4 normally in down position. When the solenoid is energized its core raises the finger H and causes the latter to trip or raise an indicator i5, moving the latter from normal. to indicating position the effect of which is to initiate a change in loom operation. The transformer T has a primary I6 connected across the power line and has a secondary ll pro- Viding low voltage. such as 12 volts.

Those parts of the system thus far described are of common construction and have been used in electric detecting systems as heretofore employed. The detector D may be as set forth in Payne Patent No. 1,924,197 and the solenoid may operate mechanism similar to that shown in Turner Patent No. 2,128,974.

In previously used electrical detector systems the parts D, I! and S have been connected in series and the solenoid has been energized from the transformer secondary whenever the detector fingers I0 and II have engaged a bare bobbin F. Under these conditions, however, it has been necessary for the detector fingers i0 and II to engage the bobbin ferrule an interval of time equal at least to that required for the complete energization of the solenoid, and it has been this condition which has required a considerable rearward displacement of the detector fingers when indicating weft exhaustion.

In order that the solenoid 8 may be effectively energized by a very short interval of contact between the detector fingers i0 and II and the ferrule F we employ a relay R and a condenser C. The binding posts 20 and 2i are connected to the opposite ends of the secondary l1 and post 20 is connected electrically by a wire 22 to detector finger H, while post 2| is connected by wire 23 to one end of the relay R and one side of the condenser 0. Wire 24 connects the other end of the relay and the other side of the condenser electrically to the detector prong or finger ID.

The relay has an armature 25 which when attracted by the relay engages contact 26 connected by wire 21 to one side of the solenoid, the other side of which is connected by wire 28 to binding post 20. By means of wire 29 the armature 25 is connected to wire 23. When armature 25 engages contact 26 the solenoid S will be energized by the secondary ll.

Under normal operation when ample weft is on the bobbin both the relay and solenoid will be deenergized, and the condenser C will be uncharged during the detecting period due to the fact that ferrule F is covered by weft, thus preventing electric connection of the prongs Ill and II with the ferrule. When the ferrule F is depleted, however, and it engages the detector fingers during the detecting interval, current flows in the following detecting circuit: binding post 20, wire 22, detector finger ll, ferrule F, detector finger [0, wire 24, through both the condenser and the relay to wire 23 and thence to binding post 2|. This circuit will be closed for a very brief period at any time during the detecting period if ferrule F is bare, without regard to whether the secondary is supplying a positive or a negative alternation.

Current flowing in this circuit even for a very brief interval of time will charge the condenser C and will cause an initial stage in the energization of the relay R. The interval of contact between the fingers ill and II and the ferrule F, however, is too short to complete effective energization of the relay R. As soon as the detector contact is broken due to backward movement of the bobbin B as the lay recedes the electricity stored in the condenser flows through a discharge circuit in which the condenser is in series with the relay and energizes the latter through its secondary stage of energization which will be considerably longer than the primary or initial stage. By choosing a condenser of proper capacity the relay will hold armature 25 against contact 26 long enough to cause movement of indicator I5 to indicating position by the solenoid.

In the first modification shown in Fig. 2 a resistance R may be inserted in the discharge circuit to prolong the flow of current from the condenser should the resistance of the relay not be high enough for this purpose.

As already stated the condenser contemplated in the circuits shown in Figs. 1 and 2 should preferably be non-polarized, since the indication of exhaustion is very brief and can occur during either the positive or negative alternation of the current supplied by the secondary l1. Where polarized electrolytic condensers are desired the third form of the invention shown in Fig. 3 can be employed wherein polarized condensers C and C2 have their positive ends connected respectively to wires 24 and 22. With these two polarized condensers, each capable of operating the relay satisfactorily, the indication can occur at any time in the cycle of the alternating current, and one or the other of them will be charged. The reason for using the polarized condensers is that they are ordinarily cheaper than the type of condenser shown in Figs. 1 and 2.

By designing the proportion of the lifter l4 and the indicating finger li a comparatively short upward movement of the solenoid core I2 can be made to give a complete movement to the indicator II. Under these conditions the solenoid can be effectively energized in a shorter interval of time than would be possible if the core were required to move a greater distance. The size of the condenser C or the condenser C' and C2 will bear some relation to the length of travel of the solenoid core, the condensers being larger when the core has the greater movement. We have been able to secure a complete movement of the finger I I by a contact between the ferrule and the bobbin fingers having a duration of only of a second.

From the foregoing it will be seen that we have provided an extremely sensitive and simple electric weft detecting system for a loom wherein a condenser is discharged during a very brief detecting interval and thereafter discharges through the relay. For certain features of our invention the relay R may be considered as an electromagnetic device which when energized effects a change in loom operation. It will further be seen that the circuit operates on low voltage and that the contact between the ferrule and the detector fingers is for an interval of time of the order of thousandths of seconds, and much shorter than that required for the effective energization of the relay. Because of this very brief contact the single strands of yarn which remain on the ferrule immediately before depletion are not injured, since the ferrule scarcely touches the detector fingers when giving indication. It will also be seen that either non-polarized or polarized condensers can be used and it will further be seen that the resistance R. can be utilized either to prolong the time of discharge of the condenser when the resistance of the relay is relatively low, or permit the use of a smaller capacity condenser. Furthermore, the condenser can be charged on any alternation of the current, and is connected directly to the source of power by the detector. By the? word "directly" used in cer-' tain of the claims we mean a connection such that there is no objectionable drop of electric potential between the detector electrodes and the condenser or electro-magnetic device connected to them. The condenser has the added advantage of arresting objectionable sparking at the detector fingers when an indication of weft exhaustion is given.

Havingthus described our invention it .will be seen that changes and modifications may be made therein by those skilled in the art without departing from the spirit and scope of the in vention and we do not wish to be limited to the details herein disclosed, but what we claim is: In an electric weft detector system for a loom having a detector which electrically connects two normally disconnected electrodes for a given interval of time when indicating weft exhaustion, an electromagnetic device which-when effectively energized initiates a change in loom operation, but which requires a given period of denser normally discharged and connected in parallel with said device and directly connected to one of said electrodes, and electric circuit means including said detector electrodes and source and operative upon electric connection of said electrodes to cause the source to charge said condenser with electricity which flows through said detector electrodes, said condenser upon electric disconnection of said electrodes discharging through said device long enough to cause effectlve energization thereof.

4. In an electric weft detector system for a loom having a detector which electrically connects two normally disconnected electrodes upon indication of weft exhaustion, the loom having an electromagnetic device which when'effectively energized initiates a change in loom operation, said electrodes when electrically connected during a detecting operation of the loom remaining connected for an interval of time shorter than that required for effective energization of said device, a source of electric power, an electric contime longer than said given interval for the effective energization thereof, a source of electric power directly connected electrically with one of said electrodes and said device, electric condenser means normally discharged but capable of being charged with electricity, said condenser means being directly connected to one of said electrodes. and electric circuit means including the detector electrodes, said source, relay and condenser means, said circuit means being closed to charge said condenser when the detector electrodes are electrically connected and said condenser thereafter discharging through said electromagnetic device to the end of said given period.

2. In an electric weft detector system for a loom having a detector which electrically connects two normally disconnected electrodes for a given interval of time when indicating weft exhaustion, an electromagnetic device which when effectively energized initiates a change in loom operation, said device being directly connected to one of said electrodes and requiring for the effective energization thereof a time longer than said given interval, a source of electric power, a normally discharged electric condenser connected in parallel with said device, and electric circuit means including said detector electrodes, source and device in series and operative upon electric connection of said electrodes dur il'lg said given interval to energize said device and also cause said source to charge said condenser, said condenser thereafter discharging through said device for a sumciently long time to cause effective energization thereof. I

3. In an electric weft detector system for a loom having a detector which electrically connects two normally disconnected electrodes for a given interval of time when indicating weft exhaustion, an electromagnetic device which when effectively energized f0r.a period of time longer than said interval initiates a change in loom operation, a source of electricity, an electric condenser connected with said device and directly connected to one of saidelectrodes, and circuit means closed by electric connection of said electrodes and connecting the source to the condenser, said source thereupon charging the condenser, and said condenser thereafter discharging through said device and causing current to flow therethrough sufficiently lon to cause effective energizing thereof.

5. In an electric weft detector system for a loom having a detector which electrically connects two normally disconnected electrodes upon indication of weft exhaustion, the loom having an electromagnetic device which when effectively energized initiates a change in loom operation, said electrodes when electrically connected by the detector during a detecting operation of the loom remainin closed for an interval of time shorter than that required for effective energization of said device, a source of electric power supplying current which has positive and negative alternations, electric condenser means connected across the device and directly connected to one, of said electrodes, and electric circuit means including said source, device, condenser means and detector electrodes and operative upon electric connection of said electrodes during either a positive or a negative alternation of the current to charge said condenser means, the latter thereafter discharging through said device to cause effective energization thereof.

6. In an electric weft detector system for a loom having a detector which electrically connects two normally disconnected electrodes upon indication of weft exhaustion, the loom having an electromagnetic device which when effectively energized initiates a change in loom operation, said electrodes when electrically connected by the detector durin a detecting operation of the loom remaining closed for an interval of time shorter than that required for effective energization of said device, a transformer the secondary of which supplies alternating current, electric condenser means connected across said device, the latter being connected directly to one of said electrodes, and electric circuit means including said secondary, device, condenser means and said detector electrodes and operative upon electric connection of said electrodes to charge the condenser means with electric power derived from the secondary, said condenser means thereafter discharging through said device to cause effective energization thereof.

7. In an electric weft detector system for a loom having a detector which electrically connects two normally disconnected electrodes upon indication of weft exhaustion, the loom having an electromagnetic device which when effectively energized initiates a change in loom operation, said electrodes when electrically connected by the detector during a detecting operation of the loom remaining closed for an interval of time shorter that that required for effective energization of said device, a source of alternating current, condenser means comprising a plurality of polarized condensers, and electric circuit means including said detector electrodes, source, and condenser means, the positive side of at least one of said condensers being connected to said circuit on one side of said device and the positive side of another of said condensers being connected to said circuit on the other side of said device, said circuit means when closed by electric connection of said electrodes charging at least one of said condensers, the charged condenser thereafter dischargin through said device a sufficiently long time to cause effective energization thereof.

8. In an electric weft detector system for a 100m having a detector which electrically connects two normally disconnected electrodes upon indication of weft exhaustion, the loom having an electromagnetic device which when effectively energized initiates a change in loom operation, said electrodes when electrically connected by the detector during a detecting operation of the 100m remaining closed for an interval of time shorter than that required for effective energization of said device, a source of alternating current, condenser means including a plurality of polarized condensers each having a positive end, electric circuit means including the electrodes, source and condenser means and effective when closed by the detector electrodes to charge at least one of said condensers by electric power derived from said source and without regard to the direction in which current is flowing in the latter, and a second circuit including said condenser means and device into which the condenser means discharges for a sufficiently long time to cause effective energization of the device.

9. In an electric weft detector system for a loom having a detector which electrically connects two normally disconnected electrodes upon indication of weft exhaustion, the loom having an electromagnetic device which when effectively energized initiates a change in loom operation, said electrodes when electrically connected by the detector during a detecting operation of the loom remaining closed for an interval of time shorter than that required for effective energize,- tion of said device, a source of alternating current, two polarized condensers connected across said device and each having a negative end and a positive end, electric circuit means including the electrodes, source and said condensers, the positive end of one'of said condensers and the negative end of the other condenser being connected to said circuit on the same side of said source, said circuit when closed by the detector electrodes charging at least one of said condensers irrespective of the direction in which current is flowing in the source, and a second circuit means connected to the first circuit means and including the condensers and device into which the charged condenser discharges to cause effective energization of the device.

10. In an electric weft detector system for a loom having a detector which electrically connects two normally disconnected electrodes for a given interval of time when indicating weft exhaustion, an electromagnetic device which when effectively energized initiates a change in loom operation but which requires electric current to flow therethrough for a given period of time longer than said given interval for the effective energization thereof, a source of electric power, electric condenser means, electric circuit means directly connectin said device with one of said electrodes and including said source and condenser means and closed by the detector electrodes to charge said condenser means from said source, an electric resistance, and means constituting a series circuit including said condenser means, said resistance, and said device, the condenser means discharging into said series circuit through said resistance and device to effectively energize the latter.

VICTOR F. SEPAVICH. JOHN C. MAN OOG.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,146,611 Young Feb. 7, 1939 2,377,102 Payne May 29, 1945 2,233,483 Metcalf Mar. 4, 1941 FOREIGN PATENTS Number Country Date 400,132 Great Britain Oct. 19, 1933 

